Intraoperatively adjusting guide alignment

ABSTRACT

An alignment guide includes a main body sized and shaped to contact the proximal end of a tibia, and a retaining guide coupled to the main body. The retaining guide includes guide surfaces and is adjustable relative to the main body such that an operator can intra-operatively adjust the position of the guide surfaces relative to the main body to capture the anterior and posterior cruciate ligament between the guide surfaces.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of U.S. patent applicationSer. No. 14/420,437, filed Feb. 9, 2015, and titled “Intraoperativelyadjusting guide alignment,” which is a U.S. national stage filing under35 U.S.C. § 371 of PCT Application No. PCT/US2013/054280, filed Aug. 9,2013, and titled “Intraoperatively adjusting guide alignment,” whichclaims priority to and the full benefit of U.S. Provisional ApplicationSer. No. 61/681,487, filed Aug. 9, 2012, and titled “INTRAOPERATIVELYADJUSTING GUIDE ALIGNMENT,” the entire contents of each of which areincorporated herein by reference.

BACKGROUND

Cutting guides are used during orthopaedic procedures to insert pins inhone and guide resections to the bone to prepare the bone for receipt ofan implant. For example, during bi-cruciate retaining total kneearthroplasty, a cutting guide used to prepare the proximal end of apatient's tibia is designed the leave intact portions of the tibialeminence that function as attachment sites for the anterior andposterior cruciate ligaments.

SUMMARY

A cutting guide for preparing the proximal end of a patient's tibia isdescribed in International Application WO 2012/051542, titledPatient-Matched Instrumentation and Methods, hereby incorporated byreference in its entirety. Prior to placing the cutting guide on thebone, an alignment guide can be used to preposition alignment pins overwhich the cutting guide is subsequently placed to guide bone resections.

An alignment guide can include a ligament retaining guide that isadjustably mounted to a main body of the cutting guide to allow theoperator to intra-operatively adjust the position of the retainingguide. Adjusting the retaining guide aligns, for example, pin receivingholes of the retaining guide through which the alignment pins are placedin the bone.

In a particular example, the alignment guide is configured to mount tothe proximal end of a patient's tibia. The alignment guide has a bonemount, for example, a portion of the alignment guide that defines thepin receiving holes, and a pair of horizontal rods spaced to capture theanterior and posterior cruciate ligaments therebetween that are used tovisualize subsequent eminence resections.

According to one aspect, an alignment guide includes a main body sizedand shaped to contact the proximal end of a tibia, and a retaining guidecoupled to the main body. The retaining guide includes guide surfacesand is adjustable relative to the main body such that an operator canintra-operatively adjust the position of the guide surfaces relative tothe main body to capture the anterior and posterior cruciate ligamentbetween the guide surfaces.

Embodiments of this aspect may include one or more of the followingfeatures.

The retaining guide is coupled to the main body such that the positionof the retaining guide is rotationally and linearly adjustable relativeto the main body. The retaining guide includes a bone mount that definesthrough holes. The main body includes a horseshoe shaped upper portionhaving surfaces for contacting the proximal surface of the tibia, and alower portion having surfaces for contacting the anterior face of theproximal end of the tibia. The bone contacting surfaces of the main bodycomprise patient-matched surfaces. The main body defines a slot.

The main body defines a through hole that receives the retaining guide,and the retaining guide includes a shaft received in the through holewith the shaft being rotatable relative to the main body. The retainingguide includes a bone mount coupled to the shaft for linear motionrelative to the shaft.

According to another aspect, a method includes positioning an alignmentguide on the proximal tibia, the alignment guide including a main bodyand a retaining guide; and intra-operatively adjusting the position ofthe retaining guide relative to the main body to capture the anteriorand posterior cruciate ligament.

The details of one or more embodiments are set forth in the accompanyingdrawings and the description below. Other features, objects, andadvantages will be apparent from the description and drawings, and fromthe claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an alignment guide.

FIG. 2 is another perspective view of the alignment guide.

FIG. 3 is a perspective view of a main body of the alignment guide.

FIG. 4 is a perspective view of a cruciate retaining guide of thealignment guide.

FIG. 5 illustrates a tibia after plateau and eminence resections havebeen made.

DETAILED DESCRIPTION

Referring to FIG. 1, an alignment guide 10 for placing pins for use inaligning a cutting guide that prepares a proximal tibia for receipt ofan implant during bi-cruciate retaining total knee arthroplasty includesa main body 12 and a cruciate retaining guide 14. The retaining guide 14can rotate, arrow 16, and translate, arrow 18, relative to the main body12 to provide intraoperative adjustability of the position of theretaining guide 14 relative to the main body 12.

Referring also to FIG. 2, the main body 12 includes a horseshoe shapedupper portion 20 having surfaces 22, 24 for contacting the proximalsurface of the tibia, and a lower portion 26 having a medial surface 28for contacting the anterior face of the proximal end of the tibia. Thebone contacting surfaces 22, 24, 28 of the main body are, for example,patient-matched surfaces. The lower portion 26 can also include alateral surface or have a lateral surface rather than the medial surface28.

The lower portion 26 defines a slot 30 through which alignment pins (notshown) are placed into the bone. The upper portion 20 defines throughholes 38, 40 and the lower portion 26 defines through holes 46 forreceiving fixation pins (not shown) used to fix the main body 12 to thetibia. On the anterior side of the upper portion 20 is a retaining guidemount 32 defining a through hole 42 (FIG. 3) that receives the retainingguide 14. The superior side of the upper portion 20 defines two slots 44that function as indicia to aid in aligning the retaining guide 14relative to the main body 12.

Referring to FIG. 4, the retaining guide 14 includes two horizontal rods50, 52 connected by a cross bar 54, a bone mount 58 connected to thecross bar 54 by two vertical bars 66, 68, and a shaft 56 that extendsbetween the cross bar 54 and the bone mount 58. At each end the shaft 56terminates in a rectangular block 62. One of the blocks 62 is receivedwithin a slot 64 defined by bone mount 58 and the other block 62 isreceived within a corresponding slot (not shown) defined by the crossbar 54. The blocks 62 can slide within the slots 64 to provide thetranslation along arrow 18. The shaft 56 can rotate about itslongitudinal axis, Y, within the through hole 42 of the retaining guidemount 32.

The retaining guide rods 50, 52 each have inner guide surfaces 70, 72,respectively, used to visualize the alignment of subsequent eminenceresections. The retaining guide 14 is coupled to the main body 12 viathrough hole 42 and shaft 56 such that in use the guide rods 50, 52 arepositioned to capture the cruciate ligaments therebetween. By aligningthe guide rods 50, 52 with the indicia slots 44, the operator positionsthe retaining guide 14 to achieve best fit and coverage of a presumedimplant. The operator can deviate from this alignment by adjusting theposition of the retaining guide 14. The operator may decide to deviatefrom alignment with the indicia slots 44 for the sake of aligning theeminence resections with the femur or a femoral trial in extensionand/or flexion. To allow the patient's leg to be placed in extensionwith the alignment guide 10 on the tibia, medial and lateral sections ofthe upper portion 20 of the main body 12 are made excisable from theremainder of the main body by, for example, including perforations orwebs in the upper portion.

The bone mount 58 defines two through holes 90, 92, each for receivingan alignment pin. The relative position of the holes 90, 92 and theguide surfaces 70, 72 correspond to the relative position of pinreceiving holes and cutting guide surfaces on a cutting block, forexample, a patient matched cutting block. Referring also to FIG. 5, dueto the corresponding relative positions, when the alignment pins placedthrough holes 90, 92 are subsequently used to place the cutting block,the alignment pins are positioned at the intersection of subsequenthorizontal plateau resections 310, 320 and vertical eminence resections340, 350 made using the cutting guide, creating curved sections 370 atthe intersections.

In use, after the main body 12 is fixed to the proximal end of the tibiausing pins placed through holes 38, 40, and 46, the operatorintra-operatively adjusts the position of the retaining guide 14relative to the main body 12 about arrow 16 and along arrow 18 to adjustthe position of the guide surfaces 70, 72 relative to the main body 12.Fixing the main body 12 to the tibia fixes three degrees of freedom ofmovement of the retaining guide 14. Rotation about arrow 16 and slidingalong arrow 18 permits adjustment of an additional two degrees offreedom of movement of the retaining guide 14.

When the operator determines that the guide surfaces 70, 72, and thusthe resulting vertical eminence resections 340, 350, are adequatelyspaced from the attachment sites of the cruciate ligaments, the operatorplaces the alignment pins through holes 90, 92. The operator thenremoves the alignment guide 10 leaving the alignment pins in place inthe bone, and places a cutting block over the alignment pins. Thecutting block can include patient-matched bone contacting surfaces thatcorrespond to bone contacting surfaces 22, 24, 28 of the main body 12.The discrete bone contacting surfaces allow some adjustability in theplacement of the patient-matched cutting block to allow the cuttingblock to be aligned with the alignment pins.

The main body of a patient-matched alignment guide can be created from aMRI scan and X-rays, or other imaging modalities such as CT. The mainbody can be made of nylon on a rapid prototyping machine or otherplastics, ceramics, or metals can be used. The main body can bemachined. The main body can have a different geometry and touchdifferent parts of the anatomy. The retaining guide is made, forexample, from metal and can be reusable or disposable.

Other embodiments are within the scope of the following claims.

For example, the retaining guide can be locked in a desired position.Continuous planar adjustment between the main body and the retainingguide (combined medial-lateral and internal-external) can be provided bya planar joint that has plane-to-plane contact rather than asliding/rotating joint. The retaining guide can be configured to bemoved inferior-superior in addition to medial-lateral andinternal-external to enable the retaining guide to be moved closer tothe eminence. Alternatively, part of the upper portion of the main bodycan be removable once the alignment guide 10 is pinned to the tibia sothat the retaining guide has room to drop down closer to the eminence.

In view of the foregoing, it will be seen that the several advantages ofthe invention are achieved and attained.

The embodiments were chosen and described in order to best explain theprinciples of the invention and its practical application to therebyenable others skilled in the art to best utilize the invention invarious embodiments and with various modifications as are suited to theparticular use contemplated.

As various modifications could be made in the constructions and methodsherein described and illustrated without departing from the scope of theinvention, it is intended that all matter contained in the foregoingdescription or shown in the accompanying drawings shall be interpretedas illustrative rather than limiting. Thus, the breadth and scope of thepresent invention should not be limited by any of the above-describedexemplary embodiments, but should be defined only in accordance with thefollowing claims appended hereto and their equivalents.

What is claimed is:
 1. A method comprising: positioning an alignmentguide on a proximal tibia, the alignment guide including a main bodydefining a through hole and a retaining guide, wherein the main bodyincludes an upper portion having surfaces for contacting the surface ofthe proximal tibia, and a lower portion having surfaces for contactingthe anterior face of the proximal tibia, wherein the retaining guidecomprises guide surfaces, a shaft rotatable relative to the main body,and a bone mount coupled to the shaft for linear motion relative to theshaft, wherein the retaining guide is coupled to and rotationally andlinearly adjustable relative to the main body, and wherein the throughhole receives the shaft; and intraoperatively adjusting the position ofthe retaining guide relative to the main body to capture an anteriorcruciate ligament and a posterior cruciate ligament between the guidesurfaces.
 2. The method of claim 1, wherein the surfaces of the upperportion and the lower portion of the main body comprise patient-matchedsurfaces.
 3. The method of claim 1, wherein the upper portion of themain body is horseshoe-shaped.
 4. The method of claim 1, wherein themain body further defines a slot for aligning the retaining guiderelative to the main body.
 5. A method comprising: positioning analignment guide on a proximal tibia, the alignment guide including amain body and a retaining guide; and intraoperatively adjusting theposition of the retaining guide relative to the main body to capture ananterior cruciate ligament and a posterior cruciate ligament, whereinthe main body has a guide mount, a lower portion, and an upper portion,wherein the retaining guide includes at least one horizontal rodconnected to a cross bar, a bone mount connected to the cross bar by atleast one vertical bar, and a shaft extending between the cross bar andthe bone mount, wherein each end of the shaft terminates in a slidingblock, and the sliding blocks are received in slots of the cross bar andthe bone mount, and wherein the guide mount has a through holeconfigured to receive the shaft of the retaining guide.
 6. The method ofclaim 5, wherein intraoperatively adjusting the position of theretaining guide comprises adjusting the position of the retaining guiderotationally and adjusting the position of the retaining guide linearly.7. The method of claim 6, wherein adjusting the position of theretaining guide rotationally includes rotating the retaining guiderelative to the main body.
 8. The method of claim 6, wherein adjustingthe position of the retaining guide linearly includes sliding theretaining guide relative to the main body.
 9. The method of claim 5,wherein the upper portion of the main body is horseshoe-shaped.
 10. Themethod of claim 5, wherein the sliding blocks are rectangular.
 11. Amethod comprising: positioning an alignment guide on a proximal tibia,the alignment guide including a main body and a retaining guide; andintraoperatively adjusting the position of the retaining guide relativeto the main body to capture an anterior cruciate ligament and aposterior cruciate ligament; wherein the main body has a guide mount, alower portion, and a horseshoe-shaped upper portion with a first surfaceand a second surface, the guide mount having a through hole; wherein theretaining guide includes two horizontal rods connected by a cross bar, abone mount connected to the cross bar by two vertical bars, and a shaftextending between the cross bar and the bone mount; wherein each end ofthe shaft terminates in a rectangular block, and the rectangular blocksare received in slots of the cross bar and the bone mount; and whereinthe through hole is configured to receive the shaft.